Plasma cystatin C concentration reflects the severity of coronary artery disease in patients without chronic kidney disease.

BACKGROUND This study examines whether the serum concentration of cystatin C (Cys C) correlates with the severity of coronary artery disease (CAD) and whether it provides additional information on the risk for CAD in patients without chronic kidney disease (CKD) estimated by the creatinine-based glomerular filtration rate (GFR). METHODS AND RESULTS The relationship between serum Cys C and the severity of CAD in 526 patients was investigated. Based on GFR, patients were divided into those with and without CKD. The relationship of serum Cys C with the severity of CAD was examined. Serum Cys C was closely correlated with GFR in all cases and in CKD patients, but not in non-CKD patients. The average number of stenotic coronary arteries was significantly higher in the quartiles of higher concentration of Cys C as well as in those of GFR. In 348 patients (66%) the GFR was ≥60 ml · min(-1)·1.73 m(-2). Those patients with increased Cys C (>0.90 mg/L, 143 patients) had a significantly larger number of stenotic coronary arteries than those patients with normal Cys C. CONCLUSIONS Among patients considered to be at low risk based on the estimated GFR using serum creatinine, those with high concentrations of Cys C could have severe CAD. Besides CKD, Cys C might serve as a marker of CAD severity.